FinFETs (Fin field-effect-transistors) are a technology which allows smaller and higher performance devices. FinFET structures comprise narrow isolated bars of silicon (fins) with a gate(s) on the top and the sides of the fin. With the continuing trend towards miniaturization of integrated circuits (ICs), there is a need for transistors having higher performance. Silicon-on-insulator (SOI) finFET devices have good electrical performance, but require more expensive substrates than the bulk wafers. Bulk finFETs, where there is no insulator film between the fins and the substrate, may have a lower manufacturing cost as compared with a SOI finFET. However, bulk finFETs can be more prone to leakage currents which can degrade the electrical performance and power consumption. It is therefore desirable to have improved finFET devices and methods of fabrication.